This document is focused basically on the kidney in depth...... It is very useful

1. THE KIDNEY
The kidneys are a pair of organs located in the back of the abdomen. Each kidney is about 4 or 5
inches long -- about the size of a fist.
The kidneys' functions are to filter the blood. All the blood in our bodies passes through the
kidneys several times a day. The kidneys remove wastes, control the body's fluid balance, and
regulate the balance of electrolytes. As the kidneys filter blood, they create urine, which collects
in the kidneys' pelvis -- funnel-shaped structures that drain down tubes called ureters to the
bladder.
Each kidney contains around a million units called nephrons, each of which is a microscopic
filter for blood. It's possible to lose as much as 90% of kidney function without experiencing any
symptoms or problems.

2. Kidney Conditions
 Pyelonephritis (infectionof kidneypelvis):Bacteriamayinfectthe kidney,usuallycausingback
painand fever.A spreadof bacteriafroman untreatedbladderinfectionisthe mostcommon
cause of pyelonephritis.
 Glomerulonephritis:Anoveractive immunesystemmayattackthe kidney,causinginflammation
and some damage.Bloodandproteininthe urine are commonproblemsthatoccur with
glomerulonephritis.Itcanalsoresultinkidneyfailure.
 Kidneystones (nephrolithiasis):Mineralsinurine formcrystals(stones),whichmaygrow large
enoughtoblockurine flow.It'sconsideredone of the mostpainful conditions.Mostkidney
stonespasson theirownbutsome are too large andneedto be treated.
 Nephroticsyndrome:Damage tothe kidneyscausesthemtospill large amountsof proteininto
the urine.Legswelling(edema) maybe asymptom.
 Polycystickidneydisease:A geneticconditionresultinginlarge cystsinbothkidneysthatimpair
theirfunction.
 Acute renal failure (kidneyfailure):A suddenworseninginkidneyfunction.Dehydration,a
blockage inthe urinarytract, or kidneydamage cancause acute renal failure,whichmaybe
reversible.
 Chronicrenal failure:A permanentpartial lossof kidneyfunction.Diabetesandhighblood
pressure are the mostcommon causes.
 End stage renal disease (ESRD):Complete lossof kidneyfunction,usuallydue toprogressive
chronickidneydisease. People withESRDrequire regulardialysisforsurvival.
 Papillarynecrosis:Severedamage tothe kidneyscancause chunksof kidneytissue tobreakoff
internallyandclogthe kidneys.If untreated,the resultingdamage canleadtototal kidney
failure.
 Diabeticnephropathy:Highbloodsugarfromdiabetesprogressivelydamagesthe kidneys,
eventuallycausingchronickidneydisease.Proteininthe urine (nephroticsyndrome) may also
result.
 Hypertensivenephropathy:Kidneydamage causedbyhighbloodpressure.Chronicrenal failure
may eventuallyresult.
 Kidneycancer:Renal cell carcinomaisthe mostcommon cancer affectingthe kidney.Smokingis
the most commoncause of kidneycancer.
 Interstitial nephritis:Inflammationof the connective tissue inside the kidney,oftencausing
acute renal failure.Allergicreactionsanddrugside effectsare the usual causes.
 Minimal change disease:A formof nephroticsyndrome inwhichkidneycellslookalmostnormal
underthe microscope.The disease cancause significantlegswelling(edema).Steroidsare used
to treat minimal change disease.
 Nephrogenicdiabetesinsipidus:The kidneyslosethe abilitytoconcentrate the urine,usually
due to a drug reaction.Althoughit'srarelydangerous,diabetesinsipiduscausesconstantthirst
and frequenturination.
 Renal cyst:A benignhollowed-outspace inthe kidney.Isolatedkidneycystsoccurinmany
normal people andalmostneverimpairkidneyfunction.

3. Kidney Tests
 Urinalysis:A routine testof the urine bya machine andoftenbya personlookingthrougha
microscope.Urinalysiscanhelpdetectinfections, inflammation,microscopicbleeding,and
kidneydamage.
 Kidneyultrasound:A probe placedonthe skinreflectssoundwavesoff the kidneys,creating
imagesona screen.Ultrasound can reveal blockagesinurine flow,stones,cysts,orsuspicious
massesinthe kidneys.
 Computedtomography(CTscan):A CT scannertakesa seriesof X-raysanda computercreates
detailedimagesof the kidneys.
 Magneticresonance imaging(MRIscan):A scannerusesradiowavesina magneticfieldtomake
high-resolutionimagesof the kidneys.
 Urine and bloodcultures:If aninfectionissuspected,culturesof the bloodandurine may
identifythe bacteriaresponsible.Thiscanhelptargetantibiotictherapy.
 Ureteroscopy:Anendoscope (flexibletube withacameraon itsend) ispassedthroughthe
urethraintothe bladderandureters.Ureteroscopygenerallycannotreachthe kidneys
themselves,butcanhelptreatconditionsthatalsoaffectthe ureters.
 Kidneybiopsy:Usinganeedle insertedintothe back,asmall piece of kidneytissueisremoved.
Examiningthe kidneytissue underamicroscope mayhelpdiagnose akidneyproblem.
Kidney Treatments
 Antibiotics:Kidneyinfectionscausedbybacteriaare treatedwithantibiotics.Often,culturesof
the bloodor urine can helpguide the choice of antibiotictherapy.
 Nephrostomy:A tube (catheter) isplacedthroughthe skinintothe kidney.Urine thendrains
directlyfromthe kidney,bypassinganyblockagesinurine flow.
 Lithotripsy:Some kidneystonesmaybe shatteredintosmallpiecesthatcanpass inthe urine.
Most often,lithotripsyisdone byamachine that projectsultrasoundshockwavesthroughthe
body.
 Nephrectomy:Surgerytoremove akidney.Nephrectomyisperformedforkidneycanceror
severe kidneydamage.
 Dialysis:Artificial filteringof the bloodtoreplace the lostfunctionof damagedkidneys.
Hemodialysisisthe mostcommonmethodof dialysisinthe U.S.
 Hemodialysis:A personwithcomplete kidneyfailureisconnectedtoadialysismachine,which
filtersthe bloodandreturnsitto the body.Hemodialysisistypicallydone threedaysperweekin
people withESRD.
 Peritoneal dialysis:Placinglarge amountsof aspecial fluidinthe abdomenthroughacatheter,
allowsthe bodytofilterthe bloodusingthe natural membrane liningthe abdomen.Aftera
while the fluidwiththe waste isdrainedanddiscarded.
 Kidneytransplant:TransplantingakidneyintoapersonwithESRDcan restore kidneyfunction.A
kidneymay be transplantedfromalivingdonor,ora recentlydeceasedorgandonor.

4. In Depth: Kidney
The kidneys are two bean-shaped organs that extract waste from blood, balance body fluids,
form urine, and aid in other important functions of the body.
They reside against the back muscles in the upper abdominal cavity. They sit opposite each other
on both sides of the spine. The right kidney sits a little bit lower than the left to accommodate the
liver.
When it comes to components of the urinary system, the kidneys are multi-talented powerhouses
of activity. Some of the core functions of the kidneys include:
 Waste excretion:There are many thingsyourbodydoesn’twantinside of it,andthe kidneys
helpgetridof some of them.The kidneysfilterouttoxins,excess salts,andurea,anitrogen-
basedwaste createdbycell metabolism.Ureaissynthesizedinthe liverandtransported
throughthe bloodto the kidneysforremoval.
 Water level balancing:Asthe kidneysare keyinthe productionof urine,theyreactto changes
inthe body’swaterlevel throughoutthe day.Aswaterintake decreases,the kidneysadjust
accordinglyandleave waterinthe bodyinsteadof helpingexcrete it.
 Blood pressure regulation:The kidneysneedconstantpressuretofilterthe blood.When it
dropstoo low,the kidneysincreasethe pressure.One wayisbyproducinga bloodvessel-
constrictingprotein(angiotensin) thatalsosignalsthe bodytoretainsodiumandwater.Both
the constrictionandretentionhelprestorenormal bloodpressure.
 Red bloodcell regulation:Whenthe kidneysdon’tgetenoughoxygen,theysendoutadistress
call in the formof erythropoietin,ahormone thatstimulatesthe bone marrow toproduce more
oxygen-carryingredbloodcells.
 Acid regulation:Ascellsmetabolize,theyproduce acids.Foodswe eatcaneitherincrease the
acid inour bodyor neutralize it.If the bodyisto functionproperly,itneedstokeepahealthy
balance of these chemicals.The kidneysdothat,too.
Most people are born with two kidneys, but many people can live on just one. Kidney transplant
surgeries with live donors are common medical procedures today.
Because of all of the vital functions the kidneys perform and the toxins they encounter, the
kidneys are susceptible to various problems.
Acute kidney failure is a condition in which the kidneys suddenly lose their ability to function
properly. This can occur for many reasons, including:
 Infection
 Blood-clottingdisorders
 Decreasedbloodflowcausedbylow bloodpressure
 Acute tubularnecrosis,ordeathof the tubularcellsthatdeliverurine tothe ureters
 Autoimmune kidneydisorders
 Urinary tract infections
 Complicationsfrompregnancy